In flowing wells, it is necessary to measure fluid flow velocity. The fluid can vary in weight from light natural gas to fluids heavier than water including drilling mud. In this wide range of fluid densities and highly variant viscosities, it is very helpful to measure the rate of flow of the fluid to determine the production rate of a selected well or a formation that is penetrated by the particular well. It is not possible to measure fluid flow velocity over a wide range of velocities with a highly variant flowing fluid where the same device is calibrated to provide a linear output in face of the highly variable production circumstances. To this end, it is extremely helpful to substitute different spinners so that each can be calibrated over a limited range where the data provided thereby is proportional to velocity. Each spinner is thus caibrated for a particular range, inferring that there is a range of velocities for a given weight of fluids where the output is nonlinear.
The present disclosure is directed to a velocity measuring device which incorporates a spinner cartridge assembly which locates a spinner in a fluid flow path. The device can be asembled and disassembled to remove and substitute a different spinner cartridge assembly so that different calibrations can then be implemented with the substituted assembly. It is desirable that the spinner in the assembly be able to rotate when driven by the flowing fluid, forming an output through a magnetic clutch which is observed by a coacting magnetic clutch member which connects with suitable data conversion apparatus and a telemetry system to transmit data out of the tool along a support cable. The system must therefore transmit by magnetic clutch coaction from the spinner cartridge assembly to remotely located electronic equipment which is housed within a sealed housing in the test device. If the spinner cartridge assembly is correctly installed, the magnetic clutch is positioned at a consistent location relative to the coacting magnetic clutch within the tool. Mispositioning runs the risk of poor magnetic engagement in the two clutch members.
The present apparatus features an elongate body having an internally located registration shoulder for abutting the end of a spinner cartridge assembly to thereby locate multiple assemblies at the precise location required, a feature enabling quick change if the originally installed spinner is not calibrated for the rate of flow actually encountered. The spinner is held in position by a retainer spring which forces the spinner cartridge assembly against a registration shoulder. The assembly is fabricated of an elongate sleeve which is axially hollow. At two ends of the sleeve, appropriate bearing assemblies support a central shaft which supports a spinner formed of multiple turns in the form of a helix. The fluid flow is directed axially through the sleeve to engage the spinner. It is rotated to rotate the shaft and the clutch assembly. The registration shoulder assures that coupling across the shoulder to the enclosed clutch plate properly transmits the rotation of the spinner consistently from insert to insert. Moreover, this assist in easy assembly of the device, namely, removal of one spinner cartridge assembly and replacement with another with limited use of hand tools, e.g. an Allen wrench. Quick assembly is achieved whereby proper and consistent registration is accomplished. The present apparatus is therefor summarized as an elongate body supported on a cable in a well which incorporates a flow diverter in the fashion of a petal basket. The elongate body has an inlet passage or opening at the flow diverter which opens into a central axial passage along the tool and flows out through an outlet passage. The insert supports a central shaft with a spinner on the shaft. The two ends of the shaft are supported in bearing assemblies and one end also supports a magnetic clutch plate. This clutch plate is adjacent a registration shoulder for the assembly. On the opposite side of the registration shoulder, a sealed housing encloses the second clutch plate that coacts with the first. The two clutch plates are precisely located from one another even after switching several inserts in and out of the tool because the insert is spring loaded against the registration shoulder to assure uniform spacing and positioning.